Final answer:
The answer to the teacher's question is three. The two 7-year-old students answered differently based on their perspectives.
Step-by-step explanation:
The answer to the teacher's question is that three blackbirds would be left after shooting one of them. This is because the question asks how many blackbirds are left sitting in the tree after one is shot, implying that the others did not fly away. Therefore, the correct answer is three.
The two 7-year-old students answered the question differently due to their different perspectives. The first student answered based on the mathematical concept of subtraction, while the second student answered based on the assumption that the remaining birds would fly away. This shows how perspectives can influence how people interpret and answer questions.